// Calculates the matrix element for the kinetic energy
public double kineticEnergyElement(matrix A, matrix B)
{
QRdecomposition qr = new QRdecomposition(A + B);
matrix inverse = qr.inverse();
matrix tmp = A * inverse * B * problem.getLambda();
return(3.0 / 2.0 * tmp.trace() * overlapElement(A, B));
}
public void Test_inverse()
{
matrix A = new matrix("1,2,3;0,1,4;5,6,0");
QRdecomposition qr = new QRdecomposition(A);
matrix inv = qr.inverse();
matrix inverse = new matrix("-24,18,5;20,-15,-4;-5,4,1");
/* Assert.IsTrue(inv.equals(inverse)); */
// It is true....
Assert.IsTrue(Misc.sortOfEqual(inv, inverse, 8));
}